Reducing rate of measurement cycles in subsequent discontinuous reception (DRX) cycles

ABSTRACT

A user device performs intra-frequency measurements and inter-frequency measurements at a specified rate when the user device in a first discontinuous reception (DRX) cycle, and determines a signal condition of a signal received from a serving cell. The user device selects one of multiple lower intra-frequency rates for intra-frequency measurements in subsequent DRX cycles based on the signal condition and selects one of multiple lower inter-frequency rates for inter-frequency measurements in the subsequent DRX cycles based on the signal condition. The reduction in the rate may reduce a current drain by the user device when the user device is in the subsequent DRX cycles.

RELATED CASES

The present application is a continuation of U.S. application Ser. No.13/076,153, filed Mar. 30, 2011, the entire contents of which are herebyincorporated by reference herein.

BACKGROUND

A large and growing population of users is enjoying entertainmentthrough the consumption of digital media items, such as music, movies,images, electronic books, and so on. The users employ various electronicdevices to consume such media items. Among these electronic devices(referred to herein as user device and user equipment) are electronicbook readers, cellular telephones, personal digital assistants (PDAs),portable media players, tablet computers, netbooks, laptops, and thelike. These electronic devices wirelessly communicate with acommunications infrastructure to enable the consumption of the digitalmedia items. Typically, the communications infrastructure requires thatwhen a user equipment (UE) is in a Discontinuous Reception (DRX) Mode(e.g., idle mode, CELL_PCH, and URA_PCH), the UE wakes up from a sleepmode periodically to decode any pages sent to the UE and performsvarious measurements, as defined in a standard specification, such as,for example, the 3^(rd) Generation Partnership Project (3GPP)specification. For example, the 3GGP specification indicates when campedon a Wideband Code Division Multiple Access (WCDMA) cell the UE is toperform serving cell measurements, neighboring cell detections, andneighboring cell measurements. These measurements are performed at aspecified rate, as defined by the standard specification. The amount oftime that the UE is active to perform these measurements depends uponthe number of neighbor cell measurements performed. The longer the UE isactive to perform these measurements, the greater the current drain ison the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood more fully from the detaileddescription given below and from the accompanying drawings of variousembodiments of the invention, which, however, should not be taken tolimit the invention to the specific embodiments, but are for explanationand understanding only.

FIG. 1 is a diagram of an exemplary cellular network architecture inwhich embodiments of the invention may operate.

FIG. 2 is a block diagram of one embodiment of a user device having aDRX mode rate-reduction system.

FIG. 3 is a block diagram of one embodiment of the DRX moderate-reduction system.

FIG. 4 is a flow diagram of one embodiment of a method for reducing aspecified rate at which the user device performs detection cycles andmeasurement cycles in a DRX mode.

FIG. 5 is a flow diagram of another embodiment of a method of adjustinga specified rate for performing a set of one or more measurements basedon a signal condition of a signal received from a serving cell.

FIG. 6 illustrates a DRX mode of a user device without the DRX moderate-reduction.

FIG. 7 illustrates a DRX mode of a user device with the DRX moderate-reduction according to one embodiment.

DETAILED DESCRIPTION

Methods and systems for reducing a specified rate at which a user deviceperforms detection cycles and measurement cycles in a DRX mode. The DRXmode may include an idle mode, URA_PCH mode, CELL_PCH mode, or any othermode in which the user device wakes up periodically from being asleep,and periodically decodes any pages, and performs serving cell andneighboring cell measurements. A user device may be any mobile device,most of which can connect to a network. Examples of user devices includeelectronic book readers, cellular telephones, personal digitalassistants (PDAs), portable media players, tablet computers, netbooks,and the like. A user device may connect to a network to obtain contentfrom a server (e.g., an item providing system) or to perform otheractivities. The user device may connect to one or more different typesof cellular networks. A cellular network is a radio network distributedover land areas called cells, each served by at least one fixed-locationtransceiver typically known a base station. When joined together thesecells provide radio coverage over a wide geographic area. This enables alarge number of portable transceivers of user devices to communicatewith each other and with fixed transceivers and telephones anywhere inthe network, via base stations, even if some of the transceivers aremoving through more than one cell during transmission.

In one embodiment, a user device performs a set of one or moremeasurements at a specified rate when the user device is in a DRX mode.The user device also determines a signal condition of a signal receivedfrom a serving cell, and the user device adjusts the specified ratebased on the signal condition. In one embodiment, the set ofmeasurements includes a detection cycle to detect one or moreneighboring cells, a measurement cycle to measure parameters of one ormore of the detected neighboring cells, or any combination thereof. Forexample, the measurement cycle may include performing an intra-frequencymeasurement for each of the detected neighboring cells, performing aninter-frequency measurement for each of the detected neighboring cells,and an inter-radio access technology (rat) measurement or detection forone or more of the neighboring cells. The user device performs each ofthese measurements at the same specified rate, or at individualspecified rates. Based on the signal condition, the user device adjuststhe specified rate or the individual rates of each of thesemeasurements. This rate-reduction may reduce a current drain by the userdevice when the user device is in the DRX mode.

In one embodiment, the user device performs the rate of theintra-frequency, inter-frequency, and inter-rat measurements anddetections at specified rates, as defined in a standard specification,such as the 3GPP specification. For example, when the user device is inWCDMA idle mode, URA_PCH mode, or CELL_PCH mode, the user device wakesup periodically from being asleep, and periodically decodes any pages,and performs serving cell and neighboring cell measurements, as definedby the 3GPP specification. The amount of time the user device's receiveris active depends on the number of neighboring cell measurements to beperformed. The longer the user device's receiver is active the greaterthe current drain of the user device. For example, per the 3GPPspecification, the user device is supposed to perform intra-frequency,inter-frequency, and inter-rate measurements as per rules specified inthe specification. These rules use a threshold value to indicate whenthe particular measurements should be performed or not. Using theembodiments described herein, the user device reduces the rate of theintra-frequency, inter-frequency, and inter-rat measurements anddetections when the serving cell's signal is above a threshold level(e.g., zero), and changes the rate back to what the specified rates(e.g., as defined in the standard specification) when the user devicedetects that the serving cell's signal falls below the threshold level(e.g., below zero). Doing this may significantly reduce the amount oftime the receiver of the user device is active, reducing the currentdrain. For example, by reducing the measurements and detections in idlemode by half, the rate reduction may result in current savings ofapproximately 25-30% in one embodiment. Alternatively, the ratereduction embodiments may provide more or less current savings based onother factors of the user device. The embodiments described herein mayhelp improve battery life significantly. In addition, these embodimentsmay reduce the current drain without impacting the user's experience,since the rate-reduction may delay reselection to a better neighboringcell when the serving cell's signal is still reasonably good. Forexample, when the display of the user device is turned off or the userdevice is in a sleep mode or low-power mode, the user device may use theDRX mode rate-reduction to further reduce the current drain while theuser device is in the idle mode. Alternatively, the user device mayperform the rate-reduction when other conditions apply.

In one embodiment, the user device includes a processing device that isconfigured to execute a DRX mode rate-reduction system when the userdevice is in the idle mode. The DRX mode rate-reduction system can sendan indication to a modem of the user device to indicate the change inrates, and the modem starts using the adjusted rates to reduce energyconsumption by the user device.

FIG. 1 is a diagram of exemplary cellular network architecture 100 inwhich embodiments of the invention may operate. The cellular networkarchitecture 100 may multiple cells 110, including a serving cell 104currently serving a user device 102, and neighboring cells 106. Eachcell includes a base station 108 configured to communicate with userdevices within the cell. These cells 110 may communicate with the userdevices 102 using the same frequency, different frequencies, samecommunication type (e.g., WCDMA, GSM, LTE, CDMA, WiMax, etc.), ordifferent communication types. Each of the base stations 108 may beconnected to a private, a public network 116, or both, such as theInternet, a local area network (LAN), a public switched telephonenetwork (PSTN), or the like, to allow the user devices 102 tocommunicate with other devices, such as other user devices, servercomputing systems, telephone devices, or the like.

The user devices 102 are variously configured with differentfunctionality and may include various mobile computing devices such aselectronic book readers, portable digital assistants, mobile phones,laptop computers, portable media players, tablet computers, cameras,video cameras, netbooks, notebooks, desktop computers, gaming consoles,DVD players, media centers, and the like. In some embodiments, the userdevices 102 are configured to enable consumption of one or more types ofmedia items including, for example, electronic texts (e.g., eBooks,electronic magazines, digital newspapers), digital audio (e.g., music,audible books), digital video (e.g., movies, television, short clips),images (e.g., art, photographs), and multi-media content.

In one embodiment, the user devices 102 communicate with an itemproviding system 114 via the base station 108 and network 116. The itemproviding system 114 may download items, upgrades, and/or otherinformation to the user devices 102 registered with the item providingsystem 114 via the network 116. The item providing system 114 may alsoreceive various requests, instructions and other data from the userdevices 102 via the network 116. The item providing system 114 mayoperate in the capacity of a server machine in client-server networkenvironment. The item providing system 114 may include one or moremachines (e.g., one or more server computer systems, routers, gateways)that have processing and storage capabilities to provide the abovefunctionality. Communication between the item providing system 114 and auser device 102 may be enabled via any communication infrastructure,such as the cellular network architecture 100. One example of such aninfrastructure includes a combination of a wide area network (WAN) andwireless infrastructure, which allows a user to use the user device 102to purchase items and consume items without being tethered to the itemproviding system 114 via hardwired links. The wireless infrastructuremay be provided by one or multiple wireless communications systems, suchas one or more wireless communications system, a wired communicationsystem, or any combination thereof. One of the wireless communicationsystems may be a wireless fidelity (Wi-Fi) hotspot connected with thenetwork 116. Another of the wireless communication systems may be awireless carrier system, such as illustrated in the cellular networkarchitecture 100 of FIG. 1, which can be implemented using various dataprocessing equipment, communication towers, etc. Alternatively, or inaddition, the wireless carrier system may rely on satellite technologyto exchange information with the user device 102. The communicationinfrastructure may also include a communication-enabling system that mayserve as an intermediary in passing information between the itemproviding system 114 and the wireless communication system (e.g., 100).The communication-enabling system may communicate with the wirelesscommunication system via a dedicated channel, and may communicate withthe item providing system 114 via a non-dedicated communicationmechanism, e.g., a public Wide Area Network (WAN) such as the Internet.

In one embodiment, the user device 102 includes a DRX moderate-reduction system that allows the user device 102 to reduce aninitial rate at which the user device performs at least one of adetection cycle to detect one or more neighboring cells 106 or ameasurement cycle to measure parameters of one or more detectedneighboring cells 106. This may reduce the current drain by the userdevice 102. The configuration and operations of the DRX moderate-reduction system are described below with respect to FIGS. 2-7.

FIG. 2 is a block diagram of one embodiment of a user device 102 havinga DRX mode rate-reduction system 224. The user device 102 may be anytype of computing device such as an electronic book reader, a PDA, amobile phone, a laptop computer, a portable media player, a tabletcomputer, a camera, a video camera, a netbook, a desktop computer, agaming console, a DVD player, a media center, and the like.

The user device 102 includes one or more processing devices 202, such asone or more CPUs, microcontrollers, field programmable gate arrays, orother types of processors. The user device 102 also includes systemmemory 206, which may correspond to any combination of volatile and/ornon-volatile storage mechanisms. The system memory 206 storesinformation which provides an operating system component 308, programmodules 210 including the DRX mode rate-reduction system 224, programdata 212, cell data 222, and/or other components. The user device 102performs functions by using the processing units 230 to execute the DRXmode rate-reduction system 224 and other instructions provided by thesystem memory 206. In one embodiment, the user device 102 executes a setof instructions for causing the user device to perform any one or moreof the methodologies discussed herein. The user device may be connected(e.g., networked) to other machines in a LAN, an intranet, an extranet,or the Internet. The user device 102 may operate in the capacity of aclient machine in client-server network environment. The user device 102may be any machine capable of executing a set of instructions(sequential or otherwise) that specify actions to be taken by thatmachine. Further, while only a single machine is illustrated, the term“machine” shall also be taken to include any collection of machines thatindividually or jointly execute a set (or multiple sets) of instructionsto perform any one or more of the methodologies discussed herein.

The processing device 202 represents one or more general-purposeprocessing devices such as a microprocessor, central processing unit, orthe like. More particularly, the processing device 202 may be a complexinstruction set computing (CISC) microprocessor, reduced instruction setcomputing (RISC) microprocessor, very long instruction word (VLIW)microprocessor, or a processor implementing other instruction sets orprocessors implementing a combination of instruction sets. Theprocessing device 202 may also be one or more special-purpose processingdevices such as an application specific integrated circuit (ASIC), afield programmable gate array (FPGA), a digital signal processor (DSP),network processor, or the like. As described above, the processingdevice 202 is configured to execute the DRX mode rate-reduction system224 for performing the operations and steps discussed herein.

The user device 102 may also include a data storage device 214 that maybe composed of one or more types of removable storage and/or one or moretypes of non-removal storage (e.g., read-only memory (ROM), flashmemory, dynamic random access memory (DRAM) such as synchronous DRAM(SDRAM), flash memory, static random access memory (SRAM)). The datastorage device 214 may include a computer-readable medium 216 on whichis stored one or more sets of instructions (e.g., instructions of theDRX mode rate-reduction system 224) embodying any one or more of themethodologies or functions described herein. As shown, instructions ofthe DRX mode rate-reduction system 224 may also reside, completely or atleast partially, within the system memory 206 and/or within theprocessing unit(s) 230 during execution thereof by the user device 102,the system memory 206 and the processing unit(s) 230 also constitutingcomputer-readable media. The instructions of the DRX mode rate-reductionsystem 224 may further be transmitted or received over a network via anetwork interface device.

While the computer-readable storage medium 216 is shown in an exemplaryembodiment to be a single medium, the term “computer-readable storagemedium” should be taken to include a single medium or multiple media(e.g., a centralized or distributed database, and/or associated cachesand servers) that store the one or more sets of instructions. The term“computer-readable storage medium” shall also be taken to include anymedium that is capable of storing, encoding or carrying a set ofinstructions for execution by the machine and that cause the machine toperform any one or more of the methodologies of the present invention.The term “computer-readable storage medium” shall accordingly be takento include, but not be limited to, solid-state memories, optical media,and magnetic media.

The user device 102 may also include one or more input devices 218(keyboard, mouse device, specialized selection keys, etc.) and one ormore output devices 220 (displays, printers, audio output mechanisms,etc.). The user device 102 may further include network interfacedevices, video displays (e.g., liquid crystal displays (LCDs) or acathode ray tube (CRT)).

The user device 102 further includes a wireless modem 240 to allow theuser device 102 to communicate via a wireless network (e.g., such asprovided by the wireless communication system) with other computingdevices, such as remote computers, the item providing system 114, and soforth. The wireless modem 240 allows the user device 102 to handle bothvoice and non-voice communications (such as communications for textmessages, multimedia messages, media downloads, web browsing, etc.) withthe wireless communication system 110. The wireless modem 240 mayprovide network connectivity using any type of mobile network technologyincluding, for example, cellular digital packet data (CDPD), generalpacket radio service (GPRS), enhanced data rates for GSM evolution(EDGE), universal mobile telecommunications system (UMTS), 1 times radiotransmission technology (1×RTT), evaluation data optimized (EVDO),high-speed downlink packet access (HSDPA), Wi-Fi, LTE, CDMA, WiMax, etc.

The wireless modem 240 may generate signals and send these signals topower amplifier (amp) 242 for amplification, after which they arewirelessly transmitted via antenna 244. Antenna 244 may be configured totransmit in different frequency bands and/or using different wirelesscommunication protocols. The antenna 244 may be a directional,omnidirectional, or non-directional antenna. In addition to sendingdata, antenna 244 also receive data, which is sent to wireless modem 240and transferred to processing units 230.

Though a single modem 240 is shown to control transmission by theantenna 244, the user device 102 may alternatively include multiplewireless modems, each of which is configured to transmit data via adifferent antenna and/or wireless transmission protocol. In oneembodiment, each modem includes a transceiver or a transmitter and areceiver. The processing units 230 control the modem 240.

The above-enumerated list of modules is representative and is notexhaustive of the types of functions performed by the user device 102.As indicated by the label “Other Device Functionality” 228, the userdevice 102 may include additional functions.

FIG. 3 is a block diagram of one embodiment of the DRX moderate-reduction system 224. The DRX mode rate-reduction system 224 may beimplemented as hardware (circuitry, dedicated logic, etc.), software(such as is run on a general purpose computing system or a dedicatedmachine), firmware (embedded software), or any combination thereof. Inthe depicted embodiment, the DRX mode rate-reduction system 224 includesa cell detection component 302, a cell measurement component 304, asignal condition tracking component 306, and a rate adjustment component308. The components of the DRX mode rate-reduction system 200 mayrepresent modules that can be combined together or separated intofurther modules, according to some embodiments.

The cell detection component 302 is configured to detect neighboringcells. The cell detection component 302 can store information regardingthe detected neighboring cells in a cell data store 222. The cellmeasurement component 304 is configured to perform one or moremeasurements of the detected cells. The cell measurement component 304can store the results of these measurements in the cell data store 222.In one embodiment, the cell measurement component 304 performs aninter-frequency measurement for each of the neighboring cells listed inthe cell data store 222. In another embodiment, the cell measurementcomponent 304 performs an intra-frequency measurement for each of theneighboring cells listed in the cell data store 222. In anotherembodiment, the cell measurement component 304 performs an inter-ratmeasurement or detection of one or more neighboring cells. The cellmeasurement component 304 performs each of these measurements accordingto a specified rate. In some cases, the specified rates are the initialrates, as defined in the specification. In other cases, the specifiedrates are the adjusted rates.

The signal condition tracking component 306 is configured to track thesignal condition of a signal received from the serving cell. The signalcondition tracking components 306 measures the signal conditionaccording to various techniques as described herein. In one embodiment,the signal condition tracking component 306 measures a cell qualityvalue or a cell receive (RX) level value, and uses this value as thesignal condition. In another embodiment, the signal condition trackingcomponent 306 measures one of these values, and subtracts a minimumrequired quality level and a power compensation value from this value.The signal condition is equal to the cell quality value or the cell RXlevel value after the subtraction. The power compensation value may bedetermined by subtracting a maximum RF output power from a maximumtransmission power, and the greater of the resulting value and zero isused for the power compensation value. The signal condition trackingcomponent 306 may store the results in the cell data store 222 or aseparate data store. Alternatively, the signal condition trackingcomponent 306 may not store the signal condition, but performs thecalculation when needed.

The rate adjustment component 308 is configured to adjust the specifiedrate(s) of the set of measurements performed by the cell measurementcomponent 304 based on the signal condition. In one embodiment, the rateadjustment component 308 adjusts each of the specified rates for theintra-frequency measurements, inter-frequency measurements, andinter-rat measurements or detections. In another embodiment, the rateadjustment component 308 adjusts the specified rate of the detectionsperformed by the cell detection component 302. In another embodiment,the rate adjustment component 308 adjusts the specified rates of boththe cell detection component 302 and the cell measurement component 304.

In one embodiment, the rate adjustment component 308 receives anindication from the signal condition tracking component of the signalcondition, and the rate adjustment component 308 compares the signalcondition against one or more signal condition thresholds to determinean adjusted rate. After determines the adjusted rate, the rateadjustment component 308 sends an indication of the adjusted rate to thecell measurement component 304 and/or the cell detection component 302.In another embodiment, the rate adjustment component 308 overwrites orupdates a memory location in memory (e.g., non-volatile memory) that isaccessed by the cell detection component 302 and/or the cell measurementcomponent 304.

In one embodiment, the rate adjustment component 308 adjusts one of thespecified rates to a first rate when the signal condition is less than afirst signal condition threshold, and adjusts the specified rate to asecond rate when the signal condition is equal to or greater than thefirst signal condition threshold. In this embodiment, the second rate isless than the first rate. In this embodiment, the signal conditionthreshold is used to represent a “good” signal condition. When thesignal has a “good” signal condition, the rate adjustment component 308can reduce the rate of the measurements performed during DRX mode.

In a further embodiment, the rate adjustment component 308 adjusts thespecified rate to a third rate when the signal condition is equal to orgreater than a second signal condition. In this embodiment, the thirdrate is less than the first rate, but the second rate may be between thefirst and third rate, or greater than the third rate. In anotherembodiment, the rate adjustment component 308 incrementally adjust thespecified rates as the signal condition decreases towards a first signalcondition threshold, and incrementally reduces the specified rate as thesignal condition increases away from the first signal conditionthreshold. Alternatively, other techniques of reducing and increasingthe specified rates based on the signal condition may be used as wouldbe appreciated by one of ordinary skill in the art having the benefit ofthis disclosure.

In one embodiment, the cell detection component 302 can control themodem of the user device to perform the detection cycle at the specifiedrate (e.g., initial rate or the adjusted rate). In another embodiment,the rate adjustment component 308 sends an indication directly to themodem to indicate the specified rate for performing the set ofmeasurements. Similarly, the cell measurement component 302 can controlthe modem, or the rate adjustment component 308 can send an indicationdirectly to the modem to indicate the specified rate for performing theset of measurements.

FIGS. 4-5 illustrate methods performed in accordance with variousembodiments of the invention. The methods are performed by processinglogic that may comprise hardware (circuitry, dedicated logic, etc.),software (such as is run on a general purpose computer system or adedicated machine), or a combination of both.

FIG. 4 is a flow diagram of one embodiment of a method 400 of adjustinga specified rate for performing a set of one or more measurements basedon a signal condition of a signal received from a serving cell. In oneembodiment, a user device (e.g., user device 102 of FIG. 1) performs themethod 400. In another embodiment, the DRX mode rate-reduction system224 of FIGS. 2 and 3 performs the method 400. Alternatively, othercomponents of the user device 102 can perform some or all of theoperations of method 400.

Referring to FIG. 4, method 400 starts by processing logic determining asignal condition of a signal received from a serving cell (block 402).The processing logic determines if the signal condition is good (e.g.,the signal condition is equal to or greater than a signal conditionthreshold) (block 404). If the signal condition is good, the processinglogic adjusts the specified rate (block 406) and returns to perform aset of measurements at the adjusted rate when the user device is in aDRX mode (block 408). Otherwise, if the signal condition is not good atblock 404, the processing logic maintains the specified rate, andperforms the set of one or more measurements at a specified rate whenthe user device is in a DRX mode (block 408).

In another embodiment of the method, the processing logic performs, forthe set of measurements at block 408, at least one of a detection cycleto detect one or more neighboring cells or a measurement cycle tomeasure parameters of one or more detected neighboring cells. In oneembodiment, for the measurement cycle at block 408, the processing logicperforms an intra-frequency measurement for each of the detectedneighboring cells at a first specified rate, an inter-frequencymeasurement for each of the detected neighboring cells at a secondspecified rate, and an inter-rat measurement or detection of one or moreneighboring cells at a third specified rate. The processing logic atblock 406 adjusts the first, second, and third specified rates. In oneembodiment, the first, second, and third rates are the same rate. Inanother embodiment, the first, second, and third rates are differentrates.

In another embodiment, the processing logic at block 402 measures a cellquality value for the signal condition. In another embodiment, theprocessing logic at block 402 measures a cell quality value of thereceived signal, and subtracts a minimum required quality level and apower compensation value from the cell quality value. In thisembodiment, the signal condition is equal to the cell quality valueafter the subtraction. In one embodiment, the processing logic candetermine the power compensation value by determining a maximumtransmission power level (UE_TXPWR_MAX_RACH dBm) that can be used by theuser device when accessing the serving cell on a random access channel(RACH), and determining a maximum radio frequency (RF) output power(P_MAX dBm) of the user device. The processing logic subtracts themaximum RF output power from the maximum transmission power to generatea computed value. The processing logic then determines if the computedvalue is greater than zero. If so, the processing logic uses thecomputed value as the compensation value, and if not, the processinglogic uses zero as the compensation value. In one exemplary embodiment,a max operation can be used for this calculation (e.g.,max(UE_TXPWR_MAX_RACH−P_MAX, 0) (dB)). The maximum transmission powerlevel (UE_TXPWR_MAX_RACH) may be read in the system information storedin memory (dBm). Alternatively, other techniques may be used to computethe compensation factor, as well as the cell quality value.

In another embodiment, the processing logic at block 402 measures a cellreceive (RX) level value for the signal condition. In anotherembodiment, the processing logic subtracts the minimum required qualitylevel in the serving cell, and the power compensation value from thecell RX level value, and the signal condition is equal to the cell RXlevel value after the subtraction. The minimum required quality level isbroadcast by base stations in a given cell and read by the user devicebefore camping on the cell.

In another embodiment, the processing logic at block 406 adjusts thespecified rate by adjusting the specified rate to a first rate when thesignal condition is less than a first signal condition threshold, andadjusts the specified rate to a second rate when the signal condition isgreater than the first signal condition threshold. In this embodiment,the second rate is less than the first rate. In another embodiment, theprocessing logic at block 406 further adjusts the specified rate to athird rate when the signal condition is greater than a second signalcondition threshold, the third rate being less than the first rate. Inone embodiment, the third rate is less than the second rate. In anotherembodiment, the third rate is greater than the second rate but less thanthe first rate.

In another embodiment, the processing logic at block 406 adjusts thespecified rate by incrementally increasing the specified rate as thesignal condition decreases towards a first signal condition threshold,and incrementally reduces the specified rate as the signal conditionincreases away from the first signal condition threshold. Alternatively,the processing logic can gradually increase and decrease the specifiedrate as the signal condition fluctuates. This may be done periodicallyby sampling the signal condition. This may also be done continuously.

As shown in FIGS. 6 and 7, the specified rate may be every paging cyclewhen the user device is in DRX mode, and the adjusted rate may be lessthan every paging cycle. In another embodiment, the specified rate isdefined by a standard specification, such as the 3GPP specification. Theadjusted rate is a variable rate that is less than the specified rate.The variable rate is set based on the signal condition. The variablerate may be set at discrete levels using one or more thresholds, or maybe any rate based on a linear relationship to the signal condition.Alternatively, the variable rate may have a non-linear relationship tothe signal condition.

FIG. 5 is a flow diagram of another embodiment of a method of adjustinga specified rate for performing a set of one or more measurements basedon a signal condition of a signal received from a serving cell. In oneembodiment, a user device (e.g., user device 102 of FIG. 1) performs themethod 500. In another embodiment, the DRX mode rate-reduction system224 of FIGS. 2 and 3 performs the method 500. Alternatively, othercomponents of the user device 102 can perform some or all of theoperations of method 500.

Referring to FIG. 5, method 500 starts by processing logic operating ina non-DRX mode of operation (block 502), and determines if the userdevice is in a DRX mode (block 504). If the user device is not in DRXmode, the processing logic continues in the non-DRX mode at block 502.However, if the user device is in DRX mode at block 504, the processinglogic tracks a signal condition of a signal (Sx) received from a servingcell (block 506). The processing logic compares the signal condition(Sx) against a first signal condition threshold (block 508). If thesignal condition (Sx) is less than the first signal condition threshold,the processing logic performs detection and/or measurement cycles at oneor more specified rates (block 510). Initially the specified rates canbe the initial rate(s) specified in the standard specification. Thedetection cycle(s) can be used to detect one or more neighboring cells.The detection of neighboring cells and measurements of already detectedcells can be performed during the same cycle. Also, during detection, ifa neighboring cell is detected then a measurement is also known for thatcell. The measurement cycle(s) can be used to measure parameters of oneor more detected neighboring cells. However, if the signal condition(Sx) is equal to or greater than the first signal condition threshold atblock 508, the processing logic reduces the initial rate at which theuser device performs the detection cycles and/or measurement cycles. Inone embodiment, the processing logic reduces the initial rate to adifferent rate that is less than the initial rate. Alternatively, theprocessing logic reduces the initial rate to one of multiple rates basedon one or more additional signal condition thresholds, for example,first and second rates depicted in FIG. 5.

In the depicted embodiment, the processing logic compares the signalcondition (Sx) against a second signal condition threshold (block 512).If the signal condition (Sx) is less than the second signal conditionthreshold (but greater than or equal to the first signal conditionthreshold) at block 508, the processing logic reduces the initial rateto a first rate for the detection cycle(s) and/or measurement cycle(s)(block 514), and returns to block 510 to perform the detection and/ormeasurement cycles at the specified rate. In this case, the specifiedrate is the first rate. However, if the signal condition (Sx) is equalto or greater than the second signal condition threshold at block 512,the processing logic reduces the initial rate to a second rate for thedetection cycle(s) and/or measurement cycle(s) (block 516), and returnsto block 510 to perform the detection and/or measurement cycles at thespecified rate. In this case, the specified rate is the second rate.

In another embodiment, the processing logic implements the algorithmdescribed below to adapt the rate of the intra-frequency,inter-frequency, and inter-rat neighboring cell measurements based onthe serving cell's signal conditions. When the serving cell's signalconditions are “good,” as set by a signal condition threshold, theprocessing logic keeps the rate slow, and as the signal conditionsstarts to worsen, the processing logic slowly increases the rate ofmeasurement to eventually match the initial rates, as defined in thestandard specification. One or more signal condition thresholds may beused, and the signal condition thresholds can be hard-coded, orprogrammable. For example, a non-volatile memory may store the signalcondition thresholds. The following algorithm uses the followingnotations for the initial rates and the specified number of thresholdlevels (also called threshold buckets).

R_(intra) is the rate of performing intra frequency measurements

R_(inter) is the rate of performing inter frequency measurements

R_(interrat) is the rate of performing inter-rat measurements

N_(intrasearch) is the number of threshold levels from 0 andS_(intrasearch)

N_(intersearch) is the number of threshold levels from 0 andS_(intersearch)

N_(interratsearch) is the number of threshold levels from 0 andS_(searchrat)

Sintrasearch specifies the threshold (in dB) for intra frequencymeasurements and for the HCS measurement rules.

Sintersearch specifies the threshold (in dB) for inter-frequencymeasurements and for the HCS measurement rules.

SsearchRATm specifies the RAT specific threshold in the serving cellused in the inter-RAT measurement rules.

Qqualmeas is the measured cell quality value. The quality of thereceived signal expressed in CPICH Ec/N0 (dB) for FDD cells.

Qrxlevmeas is the measured cell RX level value. This is received signal,CPICH RSCP for FDD cells (dBm).

Qqualmin is the minimum required quality level in the cell (dB).Applicable only for FDD cells.

Qrxlevmin is the minimum required RX level in the cell (dBm)

Squal is the Cell Selection quality value (dB). Applicable only for FDDcells.

Srxlev is the Cell Selection RX level value (dB)

Squal is the difference between the measured cell quality value and theminimum required quality level (Qqualmeas−Qqualmin)

Srxlev is the difference between the measured cell RX level value,minimum required RX level, and power compensation value(Qrxlevmeas−Qrxlevmin−Pcompensation)

Sx is defined as Squal for FDD cells and Srxlev for TDD cells

Pcompensation is the power compensation value. The power compensationvalue may be computed using max(UE_TXPWR_MAX_RACH−P_MAX, 0) (dB)

UE_TXPWR_MAX_RACH is the maximum TX power level an UE may use whenaccessing the cell on RACH (read in system information) (dBm)

P_MAX is the maximum RF output power of the UE (dBm)

FOR (i=1, i<=N_(intrasearch), i++)    IF (S_(x) > S_(intrasearch) * (i −1)/N_(intrasearch)) AND    (S_(x) <= S_(intrasearch) *i/N_(intrasearch))    THEN       Perform intra frequency measurements atthe rate       of 1/(R_(intra) * i)    ENDIF ENDFOR FOR (i=1,i<=N_(intersearch), i++)    IF (S_(x) > S_(intersearch) * (i −1)/N_(intersearch)) AND    (S_(x) <= S_(intersearch) *i/N_(intersearch))    THEN       Perform inter frequency measurements atthe rate       of 1/(R_(inter) * i)    ENDIF ENDFOR FOR (i=1,i<=N_(interratsearch), i++)    IF (S_(x) > S_(searchratm) * (i −1)/N_(interratsearch)) AND    (S_(x) <= S_(searchratm) *i/N_(interratsearch))    THEN       Perform inter-rat measurements atthe rate of 1/(R_(interrat) * i)    ENDIF ENDFORIn one embodiment, R_(intra), R_(inter), and R_(interrat) are the sameinitial rates. In another embodiment, the R_(intra), R_(inter), andR_(interrat) are different initial rates. It should also be noted thatthe algorithm can perform any one of these computations to reduce therate for any one or more of these rates as would be appreciated by oneof ordinary skill in the art having the benefit of this disclosure. Itshould also be noted that there may be other conditions that trigger theDRX mode rate-reduction algorithms described above with respect to FIGS.4 and 5. In one embodiment, a number of signal bars on a device can beused to decide if the DRX mode rate-reduction algorithms should be used.For example, if the signal condition is better than 3 bars, then use theDRX mode rate-reduction algorithm can be used. In another embodiment, auser device may have one or more sensors to detect when the user deviceis stationary. When stationary, the DRX mode rate-reduction algorithmmay be used. In another embodiment, if the device already has anotherservice like Wi-Fi (along with WCDMA), then the user device can use theDRX mode rate-reduction algorithm. Alternatively, other conditions maybe used as would be appreciated by one of ordinary skill in the arthaving the benefit of this disclosure.

As described herein, by reducing these rates, as well as the rates ofdetection cycles, reduce the amount of time the receiver of the userdevice is active, which reduces the current drain by the user device.For example, by reducing the intra- and inter-frequency measurements anddetections by half while in the DRX mode, may result in current savingsof approximately 25-30%. For another example, by reducing the intra- andinter-frequency measurements and detections by ¼ while in the DRX mode,may result in current savings of approximately 50-55%. Alternatively,other current savings may be achieved based on other factors. This mayhelp improve battery life significantly as would be appreciated by oneof ordinary skill in the art having the benefit of this disclosure.

FIGS. 6 and 7 illustrate paging cycles, detections, and measurementsperformed by the user device in a DRX mode with and without the DRX moderate-reduction according to one embodiment. In FIG. 6, the user devicewithout the DRX mode rate-reduction periodically wakes up from sleep andperforms a page decode operation 602 at each paging cycle (602 a-602 f).Initially, the user device performs intra- and inter-frequency neighbordetection cycles 604 to detect one or more neighboring cells, and, foreach subsequent cycle, the user device performs intra- andinter-frequency neighbor measurements 606 for each of the neighboringcells (606 a-606 d). As described herein, the more neighboring cellsdetected, the longer amount of time the receiver of the user device isactive. In addition, as illustrated in FIG. 6, the user device mayperform a GSM neighbor detection or measurement 608 in addition to thefrequency and detection measurements 604 and 606. In this embodiment,the specified rate is every paging cycle.

In FIG. 7, the user device with the DRX mode rate-reduction periodicallywakes up from sleep and performs a page decode operation 702 at eachpaging cycle (702 a-702 f). Initially, the user device performs intra-and inter-frequency neighbor detection cycles 604 to detect one or moreneighboring cells. However, unlike in FIG. 6, the user device performsthe intra- and inter-frequency neighbor measurement cycles 706 at areduced rate (706 a and 706 b). In this particular case, the user deviceperforms the intra- and inter-frequency neighbor measurement cycles 706every other cycle (half of the cycles). The user device does not performthe intra- and inter-frequency neighbor measurement cycles 706 at thesecond paging cycle 702 b and the fourth paging cycle 702 d, unlike theuser device in FIG. 6. Alternatively, other rates may be used for theintra- and inter-frequency neighbor measurement cycles 706. This reducesthe amount of time the receiver of the user device is active, thus,reducing current drain by the user device. In addition, as illustratedin FIG. 7, the user device may perform a GSM neighbor detection ormeasurement 708 in addition to the frequency and detection measurements704 and 706. Using the embodiments described herein, the user device mayadjust the rates of performing the intra- and inter-frequency neighbordetection cycles 704 and the GSM neighbor detection or measurementcycles 708 as would be appreciated by one of ordinary skill in the arthaving the benefit of this disclosure.

In the above description, numerous details are set forth. It will beapparent, however, to one of ordinary skill in the art having thebenefit of this disclosure, that embodiments of the invention may bepracticed without these specific details. In some instances, well-knownstructures and devices are shown in block diagram form, rather than indetail, in order to avoid obscuring the description.

Some portions of the detailed description are presented in terms ofalgorithms and symbolic representations of operations on data bitswithin a computer memory. These algorithmic descriptions andrepresentations are the means used by those skilled in the dataprocessing arts to most effectively convey the substance of their workto others skilled in the art. An algorithm is here, and generally,conceived to be a self-consistent sequence of steps leading to a desiredresult. The steps are those requiring physical manipulations of physicalquantities. Usually, though not necessarily, these quantities take theform of electrical or magnetic signals capable of being stored,transferred, combined, compared, and otherwise manipulated. It hasproven convenient at times, principally for reasons of common usage, torefer to these signals as bits, values, elements, symbols, characters,terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise as apparent from the above discussion, itis appreciated that throughout the description, discussions utilizingterms such as “detecting,” determining,” “prompting,” “generating,”“communicating,” “receiving,” “disabling,” or the like, refer to theactions and processes of a computer system, or similar electroniccomputing device, that manipulates and transforms data represented asphysical (e.g., electronic) quantities within the computer system'sregisters and memories into other data similarly represented as physicalquantities within the computer system memories or registers or othersuch information storage, transmission or display devices.

Embodiments of the invention also relate to an apparatus for performingthe operations herein. This apparatus may be specially constructed forthe required purposes, or it may comprise a general purpose computerselectively activated or reconfigured by a computer program stored inthe computer. Such a computer program may be stored in a computerreadable storage medium, such as, but not limited to, any type of diskincluding floppy disks, optical disks, CD-ROMs, and magnetic-opticaldisks, read-only memories (ROMs), random access memories (RAMs), EPROMs,EEPROMs, magnetic or optical cards, or any type of media suitable forstoring electronic instructions.

The algorithms and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general purposesystems may be used with programs in accordance with the teachingsherein, or it may prove convenient to construct a more specializedapparatus to perform the required method steps. The required structurefor a variety of these systems will appear from the description below.In addition, the present invention is not described with reference toany particular programming language. It will be appreciated that avariety of programming languages may be used to implement the teachingsof the invention as described herein. It should also be noted that theterms “when” or the phrase “in response to,” as used herein, should beunderstood to indicate that there may be intervening time, interveningevents, or both before the identified operation is performed.

It is to be understood that the above description is intended to beillustrative, and not restrictive. Many other embodiments will beapparent to those of skill in the art upon reading and understanding theabove description. The scope of the invention should, therefore, bedetermined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled.

What is claimed is:
 1. A method comprising: determining, by a userdevice, a signal condition of a signal received from a serving cellduring a current wideband code division multiple access (WCDMA) idlemode; comparing the signal condition against at least threeintra-frequency thresholds buckets corresponding to at least threeintra-frequency rates of performing intra-frequency detections ormeasurements of neighboring cells for subsequent WCDMA idle modes; basedon the comparing, selecting one of the at least three intra-frequencyrates of performing the intra-frequency detections or measurements asfollows: an initial intra-frequency rate when the signal condition is ina lowest of the at least three intra-frequency threshold buckets; asecond intra-frequency rate when the signal condition is in a secondlowest of the at least three intra-frequency threshold buckets, thesecond rate being a first fraction of the initial intra-frequency rate;or a third intra-frequency rate when the signal condition is in a thirdlowest of the at least three intra-frequency threshold buckets, thethird intra-frequency rate being a second fraction of the initialintra-frequency rate, wherein the third intra-frequency rate is lessthan the second intra-frequency rate; comparing the signal conditionagainst at least three inter-frequency thresholds buckets correspondingto at least three inter-frequency rates of performing an inter-frequencydetections or measurements of neighboring cells for subsequent WCDMAidle modes; based on the comparing, selecting one of the at least threeinter-frequency rates of performing the inter-frequency detections ormeasurements as follows: an initial inter-frequency rate when the signalcondition is in a lowest of the at least three inter-frequency thresholdbuckets; a second inter-frequency rate when the signal condition is in asecond lowest of the at least three inter-frequency threshold buckets,the second inter-frequency rate being a third fraction of the initialinter-frequency rate; or a third inter-frequency rate when the signalcondition is in a third lowest of the at least three inter-frequencythreshold buckets, the third inter-frequency rate being a fourthfraction of the initial inter-frequency rate, and wherein the thirdinter-frequency rate is less than the second inter-frequency rate. 2.The method of claim 1, wherein the first fraction is one over a productof the initial intra-frequency rate times two and the second fraction isone over a product of the initial intra-frequency rate times three, andwherein the third fraction is one over a product of the initialinter-frequency rate times two and the fourth fraction is one over aproduct of the initial inter-frequency rate times three.
 3. The methodof claim 1, wherein the first fraction is different than the thirdfraction, and wherein the second fraction is different than the fourthfraction.
 4. The method of claim 1, further comprising: comparing thesignal condition against at least three inter-radio access technology(inter-rat) thresholds buckets corresponding to at least three inter-ratrates of performing inter-rat detections or measurements of neighboringcells for subsequent WCDMA idle modes; and based on the comparing,selecting one of the at least three inter-rat rates of performinginter-rat detections or measurements as follows: an initial inter-ratrate when the signal condition is in a lowest of the at least threeinter-rat threshold buckets; a second inter-rat rate when the signalcondition is in a second lowest of the at least three inter-ratthreshold buckets, the second inter-rat rate being a fifth fraction ofthe initial inter-rat rate; or a third inter-rat rate when the signalcondition is in a third lowest of the at least three inter-rat thresholdbuckets, the third inter-rat rate being a sixth fraction of the initialinter-rat rate, and wherein the third inter-rat rate is less than thesecond inter-rat rate.
 5. The method of claim 4, wherein the firstfraction is one over a product of the initial intra-frequency rate timestwo and the second fraction is one over a product of the initialintra-frequency rate times three, wherein the third fraction is one overa product of the initial inter-frequency rate times two and the fourthfraction is one over a product of the initial inter-frequency rate timesthree, wherein the fifth fraction is one over a product of the initialinter-rat rate times two and the sixth fraction is one over a product ofthe initial inter-rat rate times three.
 6. The method of claim 4,wherein the first fraction, third fraction and fifth fraction aredifferent fractions, and wherein the second fraction, fourth fractionand sixth fraction are different fractions.
 7. A method comprising:performing, by a user device, a first set of neighboring cellmeasurements according to an initial rate when the user device is in afirst discontinuous reception (DRX) cycle, wherein the first set ofneighboring cell measurements comprises an intra-frequency measurementof a first neighboring cell and an inter-frequency measurement of asecond neighboring cell; determining a signal condition of a signalreceived from a serving cell; comparing the signal condition against aninitial intra-frequency threshold level and a second intra-frequencythreshold level; comparing the signal condition against an initialinter-frequency threshold level and a second inter-frequency thresholdlevel; selecting the initial rate for intra-frequency measurements insubsequent DRX cycles when the signal condition is equal to or less thanthe initial intra-frequency threshold level; selecting the initial ratefor inter-frequency measurements in subsequent DRX cycles when thesignal condition is equal to or less than the initial inter-frequencythreshold level; selecting a first intra-frequency rate forintra-frequency measurements in subsequent DRX cycles when the signalcondition is greater than the initial intra-frequency threshold leveland less than or equal to the second intra-frequency threshold level,wherein the first intra-frequency rate is less than the initial rate;selecting a second intra-frequency rate for intra-frequency measurementsin subsequent DRX cycles when the signal condition is greater than theinitial intra-frequency threshold level and greater than the secondintra-frequency threshold level, wherein the second intra-frequency rateis less than the initial rate; selecting a first inter-frequency ratefor inter-frequency measurements in subsequent DRX cycles when thesignal condition is greater than the initial inter-frequency thresholdlevel and less than or equal to the second inter-frequency thresholdlevel, wherein the first inter-frequency rate is less than the initialrate; and selecting a second inter-frequency rate for inter-frequencymeasurements in subsequent DRX cycles when the signal condition isgreater than the initial inter-frequency threshold level and is greaterthan the second inter-frequency threshold level.
 8. The method of claim7, further comprising comparing the signal condition against a thirdintra-frequency threshold level; and selecting a third intra-frequencyrate for intra-frequency measurements in subsequent DRX cycles when thesignal condition is greater than the initial intra-frequency thresholdlevel and greater than the third intra-frequency threshold level.
 9. Themethod of claim 7, further comprising comparing the signal conditionagainst a third inter-frequency threshold level; and selecting a thirdinter-frequency rate for inter-frequency measurements in subsequent DRXcycles when the signal condition is greater than the initialinter-frequency threshold level and greater than the thirdinter-frequency threshold level.
 10. The method of claim 7, furthercomprising: performing, by the user device, an intra-frequency detectionof neighboring cells and an inter-frequency detection of neighboringcells according to the initial rate in the first DRX cycle; selecting asame rate for intra-frequency detections in the subsequent DRX cycles asselected for the intra-frequency measurements; and selecting a same ratefor inter-frequency detections in the subsequent DRX cycles as selectedfor the inter-frequency measurements.
 11. The method of claim 7, furthercomprising: comparing the signal condition against an initialinter-radio access technology (inter-rat) threshold level and a secondinter-rat threshold level; selecting the initial rate for inter-ratmeasurements in subsequent DRX cycles when the signal condition is equalto or less than the initial inter-rat threshold level; selecting a firstinter-rat rate for inter-rat measurements in subsequent DRX cycles whenthe signal condition is greater than the initial inter-rat thresholdlevel and less than or equal to the second inter-rat threshold level;and selecting a second inter-rat rate for inter-rat measurements insubsequent DRX cycles when the signal condition is greater than theinitial inter-rat threshold level and greater than the second inter-ratthreshold level.
 12. The method of claim 11, further comprisingcomparing the signal condition against an third inter-rat thresholdlevel; and selecting a third inter-rat rate for inter-rat measurementsin subsequent DRX cycles when the signal condition is greater than theinitial inter-rat threshold level and greater than the third inter-ratthreshold level.
 13. The method of claim 11, further comprising:performing, by the user device, an inter-radio access technology(inter-rat) detection of neighboring cells according to the initial ratein the first DRX cycle; and selecting a same rate for inter-ratdetections in the subsequent DRX cycles as selected for the inter-ratmeasurements.
 14. A non-transitory computer-readable storage mediumstoring instructions that when executed by a processing device cause theprocessing device to perform the following operations: performing, byprocessing device, a first set of neighboring cell measurementsaccording to an initial rate when the processing device is in a firstdiscontinuous reception (DRX) cycle, wherein the first set ofneighboring cell measurements comprises an intra-frequency measurementof a first neighboring cell and an inter-frequency measurement of asecond neighboring cell; determining a signal condition of a signalreceived from a serving cell; comparing the signal condition against aninitial intra-frequency threshold level and a second intra-frequencythreshold level; comparing the signal condition against an initialinter-frequency threshold level and a second inter-frequency thresholdlevel; selecting the initial rate for intra-frequency measurements insubsequent DRX cycles when the signal condition is equal to or less thanthe initial intra-frequency threshold level; selecting the initial ratefor inter-frequency measurements in subsequent DRX cycles when thesignal condition is equal to or less than the initial inter-frequencythreshold level; selecting a first intra-frequency rate forintra-frequency measurements in subsequent DRX cycles when the signalcondition is greater than the initial intra-frequency threshold leveland less than or equal to the second intra-frequency threshold level,wherein the first intra-frequency rate is less than the initial rate;selecting a second intra-frequency rate for intra-frequency measurementsin subsequent DRX cycles when the signal condition is greater than theinitial intra-frequency threshold level and greater than the secondintra-frequency threshold level, wherein the second intra-frequency rateis less than the initial rate; selecting a first inter-frequency ratefor inter-frequency measurements in subsequent DRX cycles when thesignal condition is greater than the initial inter-frequency thresholdlevel and less than or equal to the second inter-frequency thresholdlevel, wherein the first inter-frequency rate is less than the initialrate; and selecting a second inter-frequency rate for inter-frequencymeasurements in subsequent DRX cycles when the signal condition isgreater than the initial inter-frequency threshold level and is greaterthan the second inter-frequency threshold level.
 15. The non-transitorycomputer-readable storage medium of claim 14, wherein the operationsfurther comprise: comparing the signal condition against a thirdintra-frequency threshold level; and selecting a third intra-frequencyrate for intra-frequency measurements in subsequent DRX cycles when thesignal condition is greater than the initial intra-frequency thresholdlevel and greater than the third intra-frequency threshold level. 16.The non-transitory computer-readable storage medium of claim 14, whereinthe operations further comprise: comparing the signal condition againsta third inter-frequency threshold level; and selecting a thirdinter-frequency rate for inter-frequency measurements in subsequent DRXcycles when the signal condition is greater than the initialinter-frequency threshold level and greater than the thirdinter-frequency threshold level.
 17. The non-transitorycomputer-readable storage medium of claim 14, wherein the operationsfurther comprise: comparing the signal condition against an initialinter-radio access technology (inter-rat) threshold level and a secondinter-rat threshold level; selecting the initial rate for inter-ratmeasurements in subsequent DRX cycles when the signal condition is equalto or less than the initial inter-rat threshold level; selecting a firstinter-rat rate for inter-rat measurements in subsequent DRX cycles whenthe signal condition is greater than the initial inter-rat thresholdlevel and less than or equal to the second inter-rat threshold level;and selecting a second inter-rat rate for inter-rat measurements insubsequent DRX cycles when the signal condition is greater than theinitial inter-rat threshold level and greater than the second inter-ratthreshold level.